1. Field of the Invention:
This invention relates to a slider attached to a slide fastener and its manufacturing method for integrally joining a pair of separate upper and lower wings.
2. Description of the Prior Art:
The slider body is integrally formed of an upper wing and a lower wing connected with each other at their tip portions by means of a connection post which is called by the term of diamond. A variety of shapes of connecting post are required since the shape of the connection post depends upon the form of fastener elements attached to the slide fastener. In the slide fastener having coil elements and zigzag elements made of monofilament, the connection post of the slider is required to be in a different shape as compared with the shape of the connection post of the slider for the slide fastener having metal elements. Since it is impossible to manufacture the connection post of the slider for the slide fastener with coil elements or zigzag elements by the press forming which is known as the conventional slider manufacturing process, the connection post is manufactured in the molding process such as the die casting process and the precision casting process. However, since these molds have complicated construction and the molded slider is required to have a beautiful appearance, not only the shape of the connection post should be selected, but also the quality of the material should be selected, so that the cost of the slider is increased.
As a means for solving the above-mentioned problems, a method is proposed to form an upper wing and a lower wing separately and join them mutually to provide a slider body. One of the solving means is disclosed in Japanese Utility Model Publication 1976/9364. The slider of said Japanese Publication is made of synthetic resin and protrusions and holes of upper and lower wings are intended to interengage and said slider is made by welding them by a welding means so as to join the upper and lower wings.
However, since the welding means of above-mentioned Japanese Publication is used against internal parts, the welded state can not be inspected from the outside to produce problems in the joining reliability. Moreover, since the connection post is made of synthetic resin, it is deformed in the welding to bring poor yielding rate.